Noise generator

Minecraft uses several different types of noise generators, specifically those making use of gradient noise, for the generation of terrain alongside other features.

There are/were noise generators that use Perlin Noise and Simplex Noise.

Example of Perlin noise, the generator frequently used ingame

Specifications

Noise generators can be defined by the following parameters:

• Octaves: The amount of different copies of this noise generator, each scaled down from the last by a factor of 2. Fewer octaves result in an unnatural appearance. More octaves added with lacunarity result in a rougher fractal appearance reminiscent of proper terrain.
• Frequency: ​
• Factor: A value the noise is multiplied with after processing (lacunarity). To make the set of values more or less extreme.
• Offset: A value added to the noise after processing. To shift the resulting set of values by this value.

These values are displayed and calculated differently in the code. Vanilla simply applies a "scale" value (frequency*(2^octaves)), defined as how much the noise generator increments per sampling (every four blocks).

Types of noise generators

Stratum colors are determined using only the first 48 bits of the 64-bit world seed in Java Edition. The strata repeat every 64 blocks on the Y-axis, and the elevation of a particular stratum can vary through a biome by as much as 4 blocks. Stratum elevations vary with respect to the X-axis only, neglecting the Z-axis.

Terrain noise generators

These are used for defining the shape of generated terrain itself.

A table of default/hardcoded settings, as well as values resulting from these, is as follows. Note that not all of these are used in vanilla, but are instead used by mods such as CubicWorldGen.

Fundamental terrain noise generators (Overworld)
Generator	Low noise		High noise		Selector noise			Depth noise
Parameter	X	Y		Z	X	Y	Z	X	Z
Offset	0				0.5			0
Factor	1				12.75			1.024
Octaves	16				8			16
Frequency	0.00522...0.00522...	0.00261...0.00261...		0.00522...0.00522...	0.01671...0.01671...	0.00835...0.00835...	0.01671...0.01671...	0.00153...0.00153...
PeriodPeriod	191.51	383.02		191.51	59.85	119.69	59.85	655.36
Increments per blockIncrements per block	171.103	85.5515		171.103	2.138	1.069	2.138	50
Increments per samplingIncrements per sampling	684.412	342.206		684.412	8.555	4.278	8.555	200
Expected 32-bit overflow distanceExpected 32-bit overflow distance	12,550,824	25,101,648		12,550,824	1,004,065,920	2,008,131,841	1,004,065,920	42,949,672
Expected 64-bit overflow distanceExpected 64-bit overflow distance	53 quadrillion53 quadrillion	107 quadrillion107 quadrillion		53 quadrillion53 quadrillion	4 quintillion4 quintillion	8 quintillion8 quintillion	4 quintillion4 quintillion	184 quadrillion184 quadrillion

Low noise

Low noise is one of the two main noise generators used for defining terrain shape. This noise generator, which uses Perlin noise, is one which is actually used as a heightmap.

High noise

This is effectively identical to low noise, but is only used when selector noise is above a given threshold value.

Selector noise

Selector noise is a third important noise generator used for terrain generation. Selector noise, using Perlin noise, dictates which of either low noise or high noise is used for generating terrain at a given position - above 1 high noise is used, below 0 low noise is used, and values between 0-1 are linearly interpolated between the low and high noise values.

Depth noise

A rather insignificant noise generator, this uses Perlin noise to make terrain slightly more nuanced in general. The possible values it can have are tightly clamped to a thin set of values. It is also only defined for the X and Z axes.

Other noise generators

These noise generators are oriented to the generation of other world features.

Decorative noise generators (Overworld)
Generator	Biome fill noise		Badlands pillar noise			Badlands clay band offset noise			Swamplands noise			Flower distribution noise
Parameter	X	Z	X	Y	Z	X	Y	Z	X	Y	Z	X	Y	Z
Offset	3		?			?			?			?
Factor	2.333...		?			?			?			?
Octaves	4		?			?			?			?
Frequency	0.00781...0.00781...		?	?	?	?	?	?	?	?	?	?	?	?
PeriodPeriod	128		?	?	?	?	?	?	?	?	?	?	?	?
Increments per blockIncrements per block	0.0625		?	?	?	?	?	?	?	?	?	?	?	?
Increments per samplingIncrements per sampling	0.25		?	?	?	?	?	?	?	?	?	?	?	?
Expected 32-bit overflow distanceExpected 32-bit overflow distance	34,359,738,368		?	?	?	?	?	?	?	?	?	?	?	?
Expected 64-bit overflow distanceExpected 64-bit overflow distance	147 quintillion147 quintillion		?	?	?	?	?	?	?	?	?	?	?	?

Biome fill noise

Upon generation, a top layer block (e.g. dirt, sand) will be placed to a certain thickness to replace the bare stone heightmap. The thickness of this dirt relies on a noise generator in vanilla.

Biome distribution

Ocean biome variants are distributed using a Perlin noise function.

The Multi Noise Biome Source (used for the Nether and the Overworld since 1.18) also uses perlin noise.

Swamp noise

Swamps use a noise generator for two purposes: for the generation of marshy areas composing a mixture of water and grass blocks, and for the variation of the two different grass colors used.

Flower noise

The placement of flowers, most prominently in flower forest and meadow biomes but possibly also elsewhere, is controlled via a noise function. Flowers generated naturally will be in different positions from those grown via bone meal, and those grown via bone meal is not dependent on world seed.

Removed noise generators

These are no longer used in the current version of the game.

Removed noise generators (Overworld)
Generator	Infdev pre-0327 noise		Island carver noise		Scale noise		Sand noise		Gravel noise		Tree density noise
Parameter	X	Z	X	Z	X	Z	X	Z	X	Z	X	Z
Offset	?		?		?		?		?		?
Factor	?		?		?		?		?		?
Octaves	16		16		16		4		4		?
Frequency	0.00195...0.00195...		0.00007...0.00007...		0.000009...0.000009...		0.00391...0.00391...		0.00391...0.00391...		?
PeriodPeriod	512		14246.96		116924.175		256		256		?
Increments per blockIncrements per block	64		2.3		0.28025		0.03125		0.03125		?
Increments per samplingIncrements per sampling	256		9.2		1.121		0.125		0.125		?
Expected 32-bit overflow distanceExpected 32-bit overflow distance	33,554,432		933,688,542		7,662,742,722		68,719,476,736		68,719,476,736		8,589,934,592
Expected 64-bit overflow distanceExpected 64-bit overflow distance	144 quadrillion144 quadrillion		4 quintillion4 quintillion		32 quintillion32 quintillion		295 quintillion295 quintillion		295 quintillion295 quintillion		?

Major noise generation prior to Infdev 20100327

Before inf-20100327, terrain was generated using 2D Perlin noise, as opposed to the 3D noise currently used by the game today.

Floating island carver noise

During Indev, floating islands were produced by using an extra noise generator to carve out air into existing terrain.

Scale noise

A noise generator that appears to only have effects in hilly areas, with little to no impact on flat low-lying regions. Its effects are now handled by biomes rather than noise generation.

Tree density noise

A noise generator existed in Infdev which dictated the density of trees in the world. This was likely removed in Alpha v1.2.0 with the introduction of biomes although is yet to be confirmed, as a similar noise generator also seems to exist in 1.12.2.

Sand noise

A noise generator was used for generating the surface block used for low-altitude areas commonly characteristic of beaches. This noise generator would determine if a given area would use sand as the surface block or not. This was probably removed in Beta 1.8.

Gravel noise

Effectively identical to sand noise and used in very similar cases, this determined where gravel would generate in beach-like areas.

Biomes prior to Beta 1.8

Biomes before Beta 1.8 used two noise generators: one of them for temperature and the other for rainfall values. The placement of biomes depended of the values of these noise generators.

Overflowing

Noise generators are capable of overflowing once hitting the integer limit for their given data type, producing spectacular results. The most notable of these are the Far Lands, resulting in noise generator overflows being referred to as types of Far Lands as a result.

In current versions of Java Edition, overflowing is not usually visible without either direct modification to terrain generation code or possibly via custom world generation.

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  Low noise overflowing

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  High noise overflowing

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  Selector noise overflowing; note how the noise pattern continues beyond the overflow for areas where the same noise is selected

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  Depth noise overflowing; note the incline (where it overflows) and the perpendicular rifts caused by it

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  Biome fill noise overflowing

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  Pre-inf-20100327 terrain generation noise overflowing

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  Floating island carver noise overflowing

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  Scale noise overflowing

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  Sand noise overflowing

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  Gravel noise overflowing